The primary goal of the proposed cohort study in Singapore is to definitively establish Chinese salted fish as a human carcinogen. Our specific aims are: (1) to demonstrate differential incidence rates of NPC between individuals at different levels of Chinese salted fish intake at recruitment, (2) to establish intake of Chinese salted fish and similar foods as a major risk factor for NPC among the Hokkien people and to show that their lower risk relative to the Cantonese is a result of their lower level of exposure, and (3) to further investigate the hypothesis that ingestion of micronutrient rich foods such as fresh vegetables and fruit exert a modifying and beneficial effect on the development of NPC. A secondary goal of this proposed research is to establish a stable cohort for long-term study of the relationship of dietary and other environmental determinants to cancer and other chronic diseases. Cancer sites with sufficient cases for study within 4-7 years include lung, stomach, colon, rectum, and female breast. A cohort of 60,000 Chinese (15,000 each of Cantonese and Hokkien men and women) aged 45-64 years and residing in Housing Estates in Singapore will be recruited over a period of 24 months. A structured questionnaire emphasizing dietary exposures will be administered in person to each participant at recruitment. The cohort will be followed for cancer occurrence through (1) annual recontact by telephone of all study subjects, (2) review of death registration records, and (3) review of cancer registration records.